You might age a lot faster if you sit too much, a new study warns.
Researchers who assessed nearly 1,500 older women found those who sat most of the day and got little exercise had cells that were biologically older by eight years than the women's actual age.
"Our study found cells age faster with a sedentary lifestyle. Chronological age doesn't always match biological age," said lead author Aladdin Shadyab. He's from the University of California, San Diego's School of Medicine.
The women, aged 64 to 95, answered questionnaires and wore a device for seven days to track their activity levels.
The study doesn't establish a cause-and-effect relationship between accelerated ageing and lack of exercise.
Still, "discussions about the benefits of exercise should start when we are young, and physical activity should continue to be part of our daily lives as we get older, even at 80 years old," Shadyab said in a university news release.
Specifically, the researchers found that women who sat for more than 10 hours a day and got less than 40 minutes of moderate-to-vigorous physical activity daily had shorter telomeres. These are caps on the end of DNA strands that protect chromosomes from deterioration.
Telomeres naturally shorten with age, but health and lifestyle factors – such as smoking and obesity – can accelerate the process. Shortened telomeres are linked with heart disease, diabetes and cancer, the researchers explained in background notes.
"We found that women who sat longer did not have shorter telomere length if they exercised for at least 30 minutes a day, the national recommended guideline," Shadyab said.
He and his colleagues plan future studies to examine the link between exercise and telomere length in younger adults and in men.
The study was published online in the American Journal of Epidemiology.